[Haskell-cafe] Re: Type System (Was: Currying and Partial Evaluation)

[Achim Schneider]

"Alfonso Acosta" <alfonso.acosta at gmail.com> wrote:

> On Jan 9, 2008 1:07 AM, Achim Schneider <barsoap at web.de> wrote:
> > > Beg pardon?  Are you referring to the type of y being described
> > > with 'b' instead of 'a'?
> > >
> > Yes.
> 
> "(a -> a) -> a" and  "(b -> b) -> b" are equivalent.
> 
> For some reason 
  ^^^^^^^^^^^^^^^

Yes, exactly that wire which isn't obscured by the boiler plate has
kindled my interest.

> ghc uses b instead of a if you are picky about it,
> just provide a  type signature explicitly.
> 
> Prelude> let {y :: (a -> a) -> a ; y f = f $ y f}
> Prelude> :t y
> y :: (a -> a) -> a


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